The present invention relates generally to agricultural mower-conditioner drive components, and more particularly relates to a variable-speed hydraulic drive apparatus for the conditioner rolls in an agricultural mower-conditioner.
Windrower mower-conditioner combinations are well known and typically comprise a cutting mechanism, a conditioning unit, and one or more deflectors to arrange the cut and conditioned crop material into a windrow. The windrower mower-conditioner combination is generally a self-propelled unit, but may also be configured to be propelled by a separate tractor. Typically, a standing crop is cut by a sickle bar or a rotating disc cutting mechanism disposed along a leading edge of the combination. The severed crop material is then directed to a conditioner unit that processes the crop for faster drying. The conditioner unit may comprise a pair of intermeshing rolls that crush the crop material passing therebetween, or a flail that breaks and scratches the crop through impact. For background information on the structure and operation of some typical disc mower-conditioners, reference is made to U.S. Pat. No. 5,778,647, issued to McLean et al., the descriptive portions thereof being incorporated herein by reference.
Disc mower-conditioners normally include one or more hydraulic motors to drive the cutting mechanism. In a disc cutter, the hydraulic motors operate at the same speed as the discs eliminating the need for reduction gearboxes between the hydraulic motors and the cutting discs. It is typical to provide an additional output driven by the hydraulic motor, but which includes a reduction gearbox for driving the conditioner rolls. This approach requires a driveline between the hydraulic drive gearbox output shaft and the conditioner rolls. Furthermore, this approach fixes the relative rotational speeds of the disc cutters and the conditioner rolls through the reduction gearbox and does not allow for independent variations in conditioner roll speed.
Obtaining the most efficient crop conditioning performance requires proper matching of the conditioner mechanism speed to the specific crop conditions. Improper conditioner mechanism speed can have an adverse affect on the way in which crop is fed into the conditioner rolls, the configuration of the resultant windrows, fuel economy, and even the condition of the crop, wherein excessive conditioner roll speed tends to excessively damage the crop material. Varying the conditioner mechanism speed in typical mower-conditioner drives requires changing drive pulleys to alter the drive ratio between the hydraulically-driven gearbox output and the conditioner rolls, an adjustment that cannot easily be performed during operation.
It would be advantageous to have a hydraulic drive for the conditioner mechanism in an agricultural mower-conditioner to reduce the cutting mechanism and conditioner mechanism drivetrain complexity. Further advantages would be realized by providing separate hydraulic drives for the cutting and conditioner mechanism that would allow variation in the relative speed of the two mechanisms thereby enabling each to be individually optimized.